Caregivers often use monitor systems to observe and/or hear their babies while they sleep in another room. These monitors are composed of a parent unit which receives sound and/or video from a monitoring unit (often referred to as a baby, kid or child unit) capable of recording and transmitting sound and/or video. Transmission is typically wireless.
Such monitors typically transmit all sounds and video from the monitored room on a continuous basis for playing by the parent unit. More advanced monitors will key a microphone to transmit only when sounds above a certain decibel are received. This avoids broadcasting sounds from normal sleep activity and movement. Since the parental unit simply plays the sound and/or video via a speaker, in two parent households, both parents are woken whenever an event triggers the transmission of sound or when a loud-enough sound is broadcast by the parent unit.